This invention relates to new and useful improvement in oil well tools, designed primarily for use with a screw-type pump normally operated in shallow to medium wells in which the screw-type pump conventionally operates by rotating the rod string to the right when viewed from the upper end thereof, inside the production string.
Conventionally, reciprocating pumps operate by moving the rod string up and down inside the production string and under these circumstances, with no rotation, a conventional tubing anchor is most efficient in such pumping operations. However it is not suitable for use with a screw-type pump normally used in shallow or medium wells that produce a lot of sand with the oil.
When a conventional tubing anchor fills with sand, it usually will not release with rotation. Also it can be extremely difficult in practice, to shear the anchor as the shear valve has to be fairly high in the string due to the nature of its operation. A conventional tubing anchor is not suitable because unless a significant amount of tension is put on the production string, the anchor will release as all tubing anchors known to applicant release to the right inasmuch as these anchors use left-hand rotation to set and right-hand rotation to release.
Unfortunately, when used with a screw-type pump, which is rotated to the right when viewed from above, sand contained with the oil will often fill the pump or the annulus and the weight of the head of fluid within the production casing will pack this sand solidly so that the rotor of the pump cannot be rotated. The torque reaction therefore tends rotate the stationary production tubing so that the pump casing and the production tubing string will also attempt to rotate and will normally rotate at the loosest joint in the string thus dropping the pump into the well sometimes together with much of the production tubing whereupon considerable time and effort must be expended in order to fish and retrieve these parts.
Furthermore, conventional tubing anchors do not permit vertical movement which is the only way in most instances, to free a sand filled pump or annulus.
Also, temperature variations which occur, often cause elongation and contraction of the equipment which is difficult to compensate for when no vertical movement is possible.
The present invention overcomes all of the these disadvantages by providing a no-turn tool at the lower end of the pump assembly and providing means to frictionally engage the tool casing and hold it stationary while setting slip blocks into the well casing thus preventing right-hand rotation from occurring during operation. This prevents the torque reaction of a pump auger assembly from rotating the pump casing and undoing production tubing joints as hereinbefore described yet at the same time does not prevent vertical movement from being initiated. This vertical movement is often needed if a sand filled pump or annulus is present particularly in view of the head of fluid which will pack this sand solidly so that the pump cannot be rotated in order to release same.
The vertical movement facility provided also takes care of temperature variations which may cause elongation and contraction of the string within the well bore.